Dual-rear-axle drive



April 30, 1929. A. D. ROBBINS 1,711,128

DUAL REAR AXLE DRIVE Filed Nov. 19, 1923 3 Sheets-Sheet 1 7 a A "OR/ YE 7.5

April 30, 1929. v RQBBINS 1,711,128

DUAL REAR AXLE DRIVE Filed Nov. 19, 1923 5 Sheets-Sheet 3 w q 7 ATTORNEY April 0, 1929. A. D. ROBBINS 1,711,128

DUAL REAR AXLE DRIVE Filed Nov. 19, 1923 s Sheets-Sheet 3 INVENTOR @M EM BY 'ML/ A TTOHAIEY Patented Apr. 30, M29.

AZOR D. ROBBINS, OF NEW YORK, N. Y., ASSIGNOR T INTERNATIONAL MOTOR COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

DUAL-REAR-AXLE DRIVE.

Application filed November 19, 1923. Serial No. 675,446.

This invention relates to certain improve- -ments in dual rear axle drives and is concerned more particularly with the relation of parts by which desirable conditions of motor practice may be satisfied, than with the particular character of the driving elements per se. lVhere dual rear axles are employed for motor vehicles it is important practically that certain alignments be approximated of the power transmission elements for the two axles and that, nevertheless, the axles themselves be disposed with the usual ground clearance and at the usual height for support of the springs. The problem of maintaining the most advantageous relationship in conformity with the best practice is difficult where, as is desirable, the power is divided at one axle and part of it led through additional shafting to the other axle. In accord-.

ance with the present invention it is proposed to provide the power for a dual rear axle drive and transmit it from one axle to another through elements and shafting which areso disposed as not to disturb the most desirable relationship of the axles and associated parts. More particularly, the invention is concerned with the application of the improvements to dual rear axles of the banjo type. The advantages and results herein referred to are attained, generally speaking, by dividing the power through gear elements disposed within a part of the housing for the differential gear of one of the axles, transmit-- ting part of the power through a shaft which is journaled directly in said housing and interposing between said last named shaft and the other axle suitable devices such as universal joint-s, desirable clearances with respect to the axle shafts themselves. The invention will be described with greater particularity in connection with the accompanying drawings, wherein:

Figure l is a view partly in horizontal section and part1 in plan showing the differential gears and housings for two dual rear axles and the power between, difierential movement as between the two rear axles being provided for by a third difi'erential gear at the point of division of the power.

Figure 2 ing the relation maintained between two do rear axles with the power transmitting shafting extending therebetween;

is a view in side elevation showif necessary, to provide for the transmitting shaft there-- Figure 3 is a view in front elevation of the foremost axle. v

Figure 4 is a view partly in horizontal section and partly in plan showing the foremost dual axle of a pair but in which the power from the propeller shaft is divided without the interposition of an additional differentialgear such as is shown in Figure 1.

Figure 5 is a view in plan thereof. As indicated hereinbefore, this invention is concerned less with the nature of the elements for driving dual rear axles than with the disposition of the elements for providing the power and transmitting partthereof from .one axle. to another. Figure 1, however, shows suitable'parts for receiving and dividing power for dual rear axles. The propelling shaft section a which is journaled in the housing I) has journaled thereon a pinion c on thehub of which is keyed a revoluble housing 0?. Planetary differential pinions 0 carried with theend of the shaft a engage the gear 0 and also mesh with a bevel gear e keyed on av shaft section f which extends rearwardly through the housing 9' for the differential gear h of the shaft sections 2', i, of one of the dual rear axles. Bearings 7', f", in the housing 9 support the shaft section f. The ievoluble casing ti heretofore referred to has keyed thereon a spur gear is which meshes with a reduction spur gear kcarried on a short shaft section k journaled in the casing I) and having on its end a final drive pinion 70 which meshes with the ring gear of the differential caring In the manner described power mm the propelling shaft section a is divided through the dif-' ferential gearing c, 0', e, in such manner that diderential act-ion'as between the shaft section f and the shaft sections 2', 2', considered as a unit, is afforded. The shaft section f extends through the banjo foremost dual rear axle an is disposed 1mportion 2' of the mediately above the shaft section '5 thereof so that compactness is assured while at the same time minim clearances are retained. By the arrangement described theshaft section f is maintained in prolon ation of the propelling shaft section a whi e the power taken ed to drive the ring gear of the differential gearing it is taken ofi through the shaft sectlom k which is disposed parallel al to and only a little below the shaft section f in a plane passing through the axes of the axle sections '5, a? thereby insuring that the power is taken rearwardly to the driven shaft sections with maximum efficiency. The shaft section 7 is coupled through universal joints 7, f", with a shaft section i journaled within the'housing Z of the rearmost dual axle. The final drive pinion f on the shaft section i engages the difi'erential gear m for the axle sections m, m of the rearmost dual axle.

Briefly stated, the shaft 7 is parallel with the shaft k but somewhat above the plane passing through the axis of the last named shaft. The axis of the shaft 7 is substantially in the same line as the axis of the short shaft section and in a plane passing through the axes of the axle sections 121/, m but inclined somewhat so as to allow the shaft f to clear the axle section 5, while the shaft k is disposedsubstantially in a plane passing through the axis of the shaft sections'i, i.

The construction described lnsures a maintenance of the most desirable relationship in the final drive elements of the two axles and in the axles themselves, as dictated by the best motor vehicle practice. At the same time, maximum power efficiency in transmission is insured. Other gear arrangements for splitting the power at one of the axles may be employed without departing from the spirit of the invention as may other details of design falling within the skill of a mechanic.

' What I claim is:

1. In combination, two pairs of live axle sections spaced apart, a rearwardly extending propeller, shaft drivingcthe foremost pair, a drive for the foremost pair connected to the propeller shaft, a shaft coaxial with the propeller shaft and extending at one side tions lying in planes through the axes of the live axles, the gears carried by the sections meshing respectively with said final drive gears, a shaft driven from a power source, means carried with one of said pairs of live axles and driven from the last named power shaft for apportioning power to the short shaft sections-and means connecting the apportioning means with the distant' short shaft; said means being offset with respect to the short shaft driving the axle sections carrying the apportioning means and being axially in alignment with. the shaft driven from the power source.

3. Ina motor vehicle having two ,pairs of live axles, differential gearing for each pair, diflerential driving pinions, final drive ring gears operatively connected with the differential driving pinions, short shaft sections.

carrying gears, the axes of the sections being respectively in planes through the axes of the live axles, the gears meshing respectively with said final drive ring gears and encased in housings unitary with the differential housings, power differential gearing to differentiate between the two pairs of live axles and encased in a housing unitary with the differential axle housing of the foremost of the said pair of axles, means operatively connecting the last named differential gearing with the two short sha'ft sections including a power shaft transmitting power to the rearmost of the pair of live axles and being ofiset with respect to the differential of the front pair'of axles and parallel to the foremost of said short shaft sections and coaxial with the rearmost short shaft section, said power shaft passing through the differential axle housing of the foremost of the pair of dual rear axles and being inclined to clear the axle over which it passes, and a shaft section connected by a universal joint to the power shaft transmitting power to the rearmost axle and by another universal joint to the short shaft section driving the final drive gear of the rearmost axle sections, such shaft section being coaxial with the ,power shaft transmitting power to the rearmost of the pair of dual axles and with the short shaft section of the rearmost of the pair of dual rear axles. 7

This specification signed this 14th day of November, A. D. 1923.

AZOR 1). ROBBINS. 

